Mainspring winding tool



March 1, 1955 D. D. INGRAM 2,703,025

MAINSPRING WINDING TOOL Filed Sept. 22. 1952 m me; 0.I713 l.

INVENTOR,

A TTORNEY United States Patent MAINSPRING WINDING TOOL Dempsey D. Ingram, Oklahoma City, Okla.

Application September '22, 1952, Serial No. 310,900

2 Claims. (Cl. 81--7.5)

The present invention relates to tools for pre-winding the mainsprings of watches, so that the wound spring may be inserted within the mainspring barrel of a watch.

Conventional pre-winding tools consist substantially of a straight shaft having a laterally projecting nib or protuberance adapted to be engaged in a through opening in the inner end of the spring. With the nib engaged in the spring opening, the shaft is rotated to wind one convolution of the spring over another and smaller convolution, until the whole spring is tightly wound helically. After the spring has been tightly wound around the shaft of the tool, it is slipped off the end of the shaft into the mainspring barrel of the watch. Such a conventional tool has an exterior appearance similar to that of the present tool as it is shown in Fig. 1 of the drawings.

The trouble with such conventional tools is that if the nib is so constructed that it projects from the shaft only a distance equal to the thickness of the mainspring, it is diflicult for the repairman to keep the spring engaged with the nib while the first convolution of the spring is being wound on the shaft. This is particularly true after the tool has been used sufficiently to get the end of the nib slightly rounded at its corners. This means that the life of such tools are very limited.

On the other hand, if the nib is made longer than the thickness of the spring, then the second spring convolution is deformed by passing over the end of the nib. This often injures the spring to the extent that the watch keeps imperfect tiine, and many times the spring breaks due to the distortion caused by the excess length of the nib.

In other words, the tool with the short spring engaging nib is unsatisfactory due to the excess time it requires of the repairman, and also due to frequent replacement because of wear, while the long nibbecl tool is impractical due to spring injury.

The prime object of the present invention is to provide a winding tool for watch mainsprings, which is easy to operate, and which at the same time will not injure the springs.

Another object is to provide a tool having a long spring engaging nib so that the first spring convolution may be wound with ease, the nib being so arranged that it recedes as the second convolution is wound around the first, thus eliminating any chance of injuring the second convolution.

A further object is to provide a tool of this class in which the nib recession is automatic, and in which the nib, when in receded position, still projects from the shaft a sufficient distance to positively retain its engagement with the spring.

An additional object of the invention is to provide a spring winding tool for the purposes set forth, which is comparatively cheap to manufacture.

Other objects will be apparent from the following description when taken in conjunction with the accompanying single sheet of drawings, wherein:

Figure l is an enlarged side elevational view;

Figure 2 is a vertical sectional view taken substantially along the line 22 of Fig. 1; and,

Figure 3 is a vertical sectional view taken substantially along the line 33 of Fig. 2.

Like characters of reference designate like parts in those figures of the drawings in which they occur.

In the drawings:

The reference numeral 1 indicates, as a whole, a hollow body preferably made of metal, said body having an abrupt front end face 2 which is fiat and smooth. Within 2,703,025 Patented Mar. 1, 1955 the bore of the body 1 is a tubular shaft 3 which projects some distance beyond the flat face 2, and which has a substantially square opening 4 in one wall, the opening 4 lying a slight distance in front of the body face 2. Since the tools of the present invention are made 'm various sizes to accommodate various widths of watch mainsprings, the center of the opening 4 should be spaced from the body face 2 a distance substantially equal to one-half thewidth of the spring which is to be wound by the tool.

Within the bore of the shaft 3, there is provided an elongated strap spring 5, the rear end of which is held in place by a set-screw 6 which passes through the wall of the body 1, and through one wall of the shaft 3., to impinge the spring 5 against the inner surface of the other wall of the shaft 3. The spring 5 extends forwardly in the shaft 3, and its forward end rigidly supports a perpendicular spring engaging nib 7, which is substantially square in cross-section. The nib 7 extends through the opening 4 in the shaft 3, and normally protrudes beyond the exterior surface of the shaft a distance equal to twice the thickness of the particular sized mainspring which is to be wound by the tool. The inherent re siliency of the spring 5 tends to maintain the nib 7 in a gully extended position, as illustrated in solid lines in The outer end surface of the nib 7 is bevelled at a forty-five degree angle, as shown in Fig. 2, for a purpose more fully described hereinbelow. The bevelled end surface of the nib 7 is indicated by the reference numeral 8. Since conventional watch mainsprings are wound in a counter-clockwise direction, the longer side of the nib 7 faces toward the left hand, or in a counterclockwise direction, when looking toward the body face 2 from the front end of the shaft 3, or in other words, as shown in Fig. 2.

In operation the inner end of a watch mainspring 9 having a through opening 10 therein, is hooked over the protruding end of the nib 7, with the end of the spring extending toward the left hand. The tool is then rotated in a counter-clockwise direction. When the first spring convolution is completely formed, the spring passes over the outer end of the nib 7, and causes the nib to recede into the shaft so that the second convolution lies flatly upon the first, with the longer face of the nib still engaged in the opening 10 of the mainspring (Fig. 2). When the mainspring 9 has been completely wound upon the shaft 3, a transfer barrel, not shown, is first placed over the helically wound spring, the shaft 3 is then rotated upon its own axis in a clockwise direction. The short side of the bevelled end of the nib 7 thereupon causes the nib to further recede into the shaft 3 to completely withdraw the nib 7 from engagement in the opening 10 in the mainspring 9. The mainspring is thereby released to nest in the transfer barrel by which it is removed from the shaft 3 of the tool. The transfer barrel, above mentioned, is conventional equipment for the watch repairman, and it is therefore deemed unnecessary to further describe its construction or usage herein. The transfer barrel is commonly used to place the helically wound mainspring in the mainspring barrel of the watch.

Obviously the invention is susceptible to some change or alteration without defeating its practicability, and I therefore do not wish to be confined to the preferred embodiment shown in the drawings and described herein, further than I am limited by the scope of the appended claims.

I claim:

1. In a pre-winding tool for watch mainsprings, the combination with a hollow shaft for receiving a helically wound mainspring, having a plurality of stacked convolutions thereon, an annular abrupt shoulder surrounding said shaft intermediate its ends for stacking thereagainst said convolutions with their similar edges contacting said shoulder, of: a mainspring engaging nib perpendicular to and slidably mounted in the wall of said hollow shaft and normally projecting laterally from said shaft adjacent said shoulder, said nib having an outwardly facing bevelled end, the longer side face thereof facing in the direction in which the mainspring is to be wound, its shorter side facing oppositely thereto, thereby permitting the second convolution of the mainspring to contact the point of said bevelled end, compressing the nib sufficiently to position its shorter side slightly inside the inner surface of the first convolution, thereby permitting the completely wound mainspring to be released from said shaft by clockwise rotation of the same; and a spring carried by said shaft normally urging said nib in an outwardly thrust position.

2. In a pre-winding tool for watch mainsprings, the combination with a hollow shaft for receiving a helically wound mainspring having a plurality of stacked convolutions thereon, an annular shoulder surrounding said shaft intermediate its ends for stacking thereagainst said convolutions with their similar edges contacting said shoulder, of: an elongated fiat spring longitudinally disposed within said shaft and rigidly attached adjacent one end; and a mainspring engaging nib rigidly carried by the free end of said spring perpendicular to and slidably mounted in the wall of said hollow shaft normally projecting laterally from said shaft adjacent said shoulder, said nib having an outwardly facing bevelled end, the longer side face thereof facing in the direction in which the mainspring is to be Wound, its shorter side facing op,- positely thereto, thereby permitting the second convolution of the mainspring to contact the point of said bevelled end compressing the nib sufliciently to position its shorter side slightly inside the inner surface of the first convolution thereby permitting the completely wound mainspring to be released from said shaft by a clockwise rotation of the same.

References Cited in the file of this patent UNITED STATES PATENTS 342,745 Gullberg May 25, 1886 1,812,494 McFarland June 30, 1931 2,628,523 Williams Feb. 17, 1953 

